The outbreak, which has hit German consumers and visitors to the country, is particularly nasty, according to health experts, who have been alarmed at how healthy, young women have been struck down with symptoms, including stomach cramps and severe diarrhoea.

On Tuesday, one death in Sweden was confirmed.

The organic cucumbers, which are thought to be at the centre of the outbreak, are believed to have originated from two sites in southern Spain, the salad growing capital of Europe, which ships vast quantities of produce to Britain every week.

However doubts have emerged over whether this area is in fact to blame, with German health officials on Tuesday afternoon admitting tests on suspect Spanish cucumbers suggested that while they were infected with E.coli, it was not the same strain that had caused so many people to fall ill.

Spain has demanded compensation for the damage caused to is agricultural sector as a result of being blamed for the outbreak.

Tesco has in the past chartered their own trains, complete with chilled carriages, to transport fresh produce as quickly as possible from the greenhouses of Murcia to British shelves within 24 hours.

According to the Fresh Produce Consortium, Britain imported 56,016 tonnes of Spanish cucumbers and gherkins in 2009, underlining how reliant this country's greengrocers and supermarkets are on the couple of thousand acres in southern Spain.

Figures from the Department for Food, the Environment and Rural Affairs indicated that Spain was responsible for well over a third of all fresh vegetable imports to Britain, with 726.3 tonnes a year.

Both the Food Standards Agency and the Health Protection Agency have stressed that there is no evidence that any infected cucumbers have entered Britain, but that consumers should wash salads before eating them.

A spokesman for the British Retail Consortium said: "All British retailers have a full traceability system in place, which are the most sophisticated type of systems in Europe.

"They can trace back all of their produce to individual farms. There is no question at all of shops taking perfectly safe cucumbers off the shelf, or for shoppers to have any concern at all about buying fresh produce."

The Fresh Produce Consortium, which represents British growers as well as importers, pointed out that at this time of year – particularly after the hot spring – "majority" of cucumbers consumed in Britain were grown in Britain. Tesco said it imported only a "small amount" of organic cucumbers from Spain, but they were not affected.

A spokesman hinted that those with concerns should stick to British: "We have the safest standards of agricultural production in the UK. Consumers can look at the label, see the country of origin and make their own decision whether they want to take anything further."

While British retailers reassured shoppers that this country was safe from the outbreak, Spanish officials have refused to accept the blame, saying it is still unclear exactly when and where the vegetables were contaminated.

Tests on two cucumbers imported from Spain and blamed for the outbreak showed the enterohamorrhagic E. coli (EHEC) bacteria was present, but not the strain responsible for the current massive contamination.

””We are disappointed by the way Germany handled the situation,” she said at a meeting of EU agricultural ministers in Debrecen, Hungary. ”From the beginning Spanish cucumbers have been named as responsible for this situation. This was said without having reliable data and we insist that it is not true,” she said.

The impact on Spain's agricultural sector as countries across Europe cleared the shelves of Spanish fruit and vegetables was described as “extremely damaging”.

Nine countries took measures to block or restrict salad vegetable imports costing Spain an estimated 200 million euros per week as orders were cancelled and trucks laden with unwanted goods were turned away.

”We have to ask for compensation not only for Spanish producers but for all the European producers concerned by the situation,” she urged her counterparts.